JP3248606B2 - Mechanical quantity sensor, strain resistance element, and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic quantity sensor capable of detecting dynamic quantities such as strain, attractive force, repulsive force, vibration, and temperature with high sensitivity based on a change in electric resistance of a strain resistor layer. About. More specifically, the present invention relates to a strain resistance element, a beam, a manufacturing method thereof, and an angular velocity sensor.

[0002]

2. Description of the Related Art As an element for converting a mechanical quantity such as strain, attractive force, repulsive force, vibration, and temperature into an electric signal, there has been an element using a strain resistor layer. As such a strain resistance element, there is an element in which a stripe-shaped metal thin film is formed on a substrate, which detects a change in electric resistance of the metal thin film due to a shape change due to strain. In addition, there is one that detects a change in electrical resistance due to strain in a silicon semiconductor whose resistance has been reduced by doping. These strain resistance elements are widely used as acceleration sensors, pressure sensors, impact sensors, or infrared detection elements other than simple strain sensors.

[0003]

A strain resistance element using a metal thin film uses a film forming process such as vacuum evaporation.
There are advantages in that a strain resistance element can be formed directly on an object for which strain is to be measured, and in that resistance change due to temperature is small. However, there is a disadvantage that the rate of change of the resistance value with respect to the strain is small, that is, the sensitivity is low.

An element using a semiconductor such as silicon has high sensitivity, but has a large change in resistance value depending on temperature.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dynamic quantity sensor such as a strain resistance element and the like, a method of manufacturing the same, and an angular velocity sensor which are excellent in stability and reliability. To provide.

[0006]

A physical quantity sensor according to the present invention is a physical quantity sensor having an electrically insulating material layer and at least a pair of electrodes in contact with the electrically insulating material layer, In the conductive material layer, a plurality of conductive fine particles are dispersed so that a tunnel current flows when a voltage is applied between the at least one pair of electrodes, and a physical quantity related to an interval between the conductive fine particles is reduced. Detection is performed based on the tunnel current, thereby achieving the above object.

[0007] The apparatus may further include a base supporting the electric insulating material layer.

[0008] The base may be a substrate on a flat plate, or a beam having both ends fixed, and a cantilever having one end fixed.

The diameter of the conductive fine particles is 1 nm to 50 nm.
It is preferably nm.

The conductive fine particles may be dispersed in a layer in the electrically insulating material layer.

The distance between the conductive fine particles is preferably 5 nm or less.

The conductive fine particles are made of aluminum (A
l), chromium (Cr), manganese (Mn), iron (F
e), cobalt (Co), nickel (Ni), copper (C
u), zinc (Zn), gallium (Ga), palladium (Pd), silver (Ag), indium (In), tin (S
n), platinum (Pt), gold (Au), or at least one metal selected from the group consisting of lead (Pb).

The electrically insulating material layer is made of an oxide, and the conductive fine particles are made of gold (Au), silver (A
g), copper (Cu), platinum (Pt), or at least one metal selected from the group consisting of palladium (Pd).

The electric insulating material layer is made of silicon (Si),
It is preferable that at least one selected from the group consisting of oxides of aluminum (Al), titanium (Ti), hafnium (Hf), silicon (Si), and nitrides of aluminum (Al) is used as a main component.

The strain resistance element according to the present invention includes an electric insulating material layer and at least a pair of electrodes in contact with the electric insulating material layer, and applies a strain generated in the electric insulating layer between the pair of electrodes. A distortion resistance element that is detected based on a flowing current,
In the electrically insulating material, a plurality of conductive fine particles are dispersed so that a tunnel current flows when a voltage is applied between the at least one pair of electrodes.
The above object is achieved.

The diameter of the conductive fine particles is 1 nm to 50 nm.
It is preferably nm.

It is preferable that the conductive fine particles are dispersed in a layered manner in the electrically insulating material layer.

The distance between the conductive fine particles is preferably 5 nm or less.

The conductive fine particles are made of aluminum (A
l), chromium (Cr), manganese (Mn), iron (F
e), cobalt (Co), nickel (Ni), copper (C
u), zinc (Zn), gallium (Ga), palladium (Pd), silver (Ag), indium (In), tin (S
n), platinum (Pt), gold (Au), or at least one metal selected from the group consisting of lead (Pb).

The electrically insulating material layer is formed of an oxide, and the conductive fine particles are made of gold (Au), silver (A
g), copper (Cu), platinum (Pt), or at least one metal selected from the group consisting of palladium (Pd).

The electrically insulating material layer is made of silicon (Si),
It is preferable that at least one selected from the group consisting of oxides of aluminum (Al), titanium (Ti), hafnium (Hf), silicon (Si), and nitrides of aluminum (Al) is used as a main component.

[0022] The electric insulating material layer and the electrode may be laminated in a plurality of layers.

The method for producing a strain-resistant element according to the present invention includes a step of forming an electrically insulating material layer in which conductive fine particles are dispersed, and a step of providing at least one pair of electrodes on the electrically insulating material layer. A method for manufacturing a strain resistance element,
The step of forming the electrically insulating material layer includes a step of alternately depositing an electrically insulating material and conductive fine particles, thereby achieving the above object.

Another method for manufacturing the strain-resistant element of the present invention includes a step of forming an electrically insulating material layer in which conductive fine particles are dispersed, a step of providing at least one pair of electrodes on the electrically insulating material layer, A method for producing a strain-resistant element, the method further comprising a step of heat-treating the electrically insulating material layer in which the conductive fine particles are dispersed, thereby controlling the size of the conductive fine particles. Thus, the above object is achieved.

The manufacturing method of the mechanical quantity sensor of the present invention, group
Providing a pair of electrodes on a plate; and forming a resistor layer including an electrically insulating material layer in which conductive fine particles are dispersed on each of the electrodes.
Forming a portion on the substrate , etching a part of the resistor layer to form a beam, and positioning at least a portion of the substrate below the beam-shaped resistor layer. Forming a beam by removing a portion to be formed, whereby the object is achieved.

[0026]

[0027] The step of forming the resistor layer may include a step of alternately depositing the electrically insulating substance and the conductive fine particles.

The method may further include a step of performing a heat treatment on the resistor layer.

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a strain resistance element used in a physical quantity sensor according to the present invention will be described with reference to FIGS. 1 (a) and 1 (b). In the specification of the present application, "dynamic quantity"
The term “strain, attractive force, repulsion, vibration, temperature, and the like” refers to “a physical quantity that affects the distance between conductive fine particles dispersed in the electrically insulating material layer”. 1A and 1B schematically show a cross section of a strain resistance element according to the present invention. In the strain resistance element shown in FIG. 1A, conductive fine particles are substantially uniformly dispersed in the depth direction of the electrically insulating material layer 3. On the other hand, in the strain resistance element shown in FIG.
Exists in a layer at a specific depth range inside. According to the strain resistance element of the present invention as shown in the drawing, when a voltage V is applied to a pair of electrodes in contact with the electrically insulating material layer, electrons are generated between the conductive fine particles dispersed in the electrically insulating material layer. Tunnel, and a so-called tunnel current flows. Regarding the tunnel current itself, research results, for example, Rev. Sci.
Instrum. 60 (2) 165,1989.

According to the present invention, a tunnel current I represented by the following equation flows through an electrically insulating material.

I = k (V / d) exp (−Aφ ^1/2 d) where k = constant d = distance between conductive fine particles (Å) A = 1.025 (eV) ^−1/2 Å ⁻¹ φ = barrier height between conductive particles (eV) From this equation, the resistance value between the conductive particles is the distance d between the particles.
Greatly depends on Therefore, distortion can be detected with high sensitivity. Except for the fact that the distance between the conductive fine particles changes due to thermal expansion, there is no direct temperature dependence of the resistance value. The present inventor has found that based on this principle, it is possible to realize a strain resistance element that has high sensitivity for detecting strain, has excellent temperature characteristics, and operates stably and reliably over a long period of time.

Hereinafter, the strain resistance element of the present invention will be described with reference to FIG. This strain resistance element includes an electrically insulating material layer 3 supported on a substrate (not shown), and a pair of electrodes 4 and 5 in contact with the electrically insulating material layer 3.
A plurality of conductive fine particles 2 are dispersed in the electrically insulating substance 3 so that a tunnel current flows when a voltage is applied between the pair of electrodes 4 and 5. When the conductive fine particles are dispersed at intervals where a tunnel current is generated, the volume ratio of the conductive fine particles in the electrically insulating material layer is 15 to 7
It became 0%.

As the substrate, those formed from various materials such as glass, metal, and resin can be used according to the application. By using a conductive material such as a metal as the substrate, the substrate can function as one of the pair of electrodes. In that case, the tunnel current is
It flows in the vertical direction of (a). In addition, without using the “substrate on a flat plate” used in a normal sense, the electrically insulating material layer 3 and the pair of electrodes 4 and 5 are directly formed on a substrate of another shape or an object to be measured for strain. May be provided.

The material of the conductive fine particles 2 may be any material having conductivity, but it is desirable to use a thermally and chemically stable material, particularly a noble metal. The size of the conductive fine particles 2 is preferably 1 to 50 nm. When the conductive fine particles 2 having a size in this range are dispersed in the electrically insulating material layer 3, the distance between the fine particles can be made relatively uniform at the nanometer level. In particular, when the conductive fine particles are grown by a sputtering method, when the size of each conductive fine particle is grown to 1 to 50 nm or less,
It has been confirmed by the present inventors that the distance between the conductive fine particles is a distance suitable for flowing a tunnel current. The most important thing is to make the distance between the particles fine enough for the tunnel current to flow.
Even if the diameter exceeds nm, it is possible to disperse the particles so that a tunnel current flows by adjusting the number density of the conductive fine particles in the electrically insulating material layer. Of course, it is not necessary to make all the distances between the fine particles existing between the electrodes the distance at which the tunnel current flows, and there is no problem even if there are fine particles electrically short-circuited with other fine particles. That is, it is sufficient that there is a portion between the electrodes where no current flows unless a tunnel current is applied. When the ratio of the conductive fine particles 2 to the electrically insulating substance 3 in the portion where the current actually flows is in the range of 15 to 70% by volume, a strain resistance element with particularly excellent sensitivity was obtained. This will be described in detail later.

Next, the strain resistance element shown in FIG. 1B will be described. In this element, since the conductive fine particles are dispersed in a layer, the required fine particles can be formed using a relatively small amount of the conductive material. In particular, when the conductive fine particles are formed by a sputtering method, the production is performed by a simple process. The element of FIG. 1B has anisotropic sensitivity characteristics in which sensitivity to strain in the in-plane direction is higher than strain in the depth direction (thickness direction) of the electrically insulating material layer 3. This is because, according to the configuration of FIG.
This is because the magnitude of the tunnel current hardly changes or does not flow at all depending on the strain in the depth direction. In addition,
In FIG. 1B, the conductive fine particles are dispersed in one layer, but the same applies to the case where the conductive particles are dispersed in a plurality of layers.
By dispersing the conductive fine particles in a layered manner in the electrically insulating thin film, it is possible to confine a portion where current flows in the electrically insulating material, and to prevent deterioration of electrical characteristics due to an atmosphere gas used. In particular, a highly reliable element can be obtained even by using conductive fine particles formed of a material that easily reacts with an atmospheric gas.

FIGS. 2A to 2C are plan views schematically showing the distribution of conductive fine particles between a pair of electrodes. In the state of FIG. 2A, the distance S between the conductive fine particles is set.
Is too large, no tunnel current flows. FIG.
In the state (b), the gap S between the particles is too small, and there is a current path (a path of a current that is not a tunnel current) with which the particles are in direct contact, so that the tunnel current does not substantially flow. On the other hand, in the state of FIG. 2C, a gap suitable for the tunnel current exists in at least a part of the current path, so that the tunnel current flows, and the magnitude of the distortion can be detected by measuring the tunnel current. .

The material of the electrically insulating material layer 3 may be any material such as an oxide, a nitride, an organic material, or the like, whose conductivity is low enough to detect a change in tunnel current. The electrodes 4, 5 are electrically connected to the conductive fine particles 2 with certainty. For example, when the conductive fine particles 2 are present in a layer in a specific depth range inside the electrically insulating substance 3, After removing at least a part of the electrically insulating substance 3 on the surface, it is necessary to form the electrodes 4 and 5 so as to be in electrical contact with a part of the conductive fine particles 2 dispersed in a layer. Silicon (Si), aluminum (Al), titanium (Ti),
Oxide of hafnium (Hf) or silicon (Si),
By using a material containing at least one selected from the group consisting of nitrides of aluminum (Al) as a main component, an element that can operate stably even in a corrosive gas or a high-temperature atmosphere can be realized.

By forming an electrode and a composite material layer in which conductive fine particles are dispersed in an electrically insulating substance on an electrically insulating substrate, the electrical connection between the conductive fine particles and the electrode is achieved. The connection becomes stable and reliable, and a highly reliable element can be manufactured. As described above, if the conductive fine particles are formed so that the diameter of the conductive fine particles is in the range of 1 nm or more and 50 nm or less, it is easy to control the distance between the fine particles to a distance at which the tunnel current flows stably. The device can be manufactured with good reproducibility. In particular,
It has been found that when the distance between the conductive fine particles is 5 nm or less, the rate of change of the resistance value with respect to the strain can be increased. In addition, by forming the shape of the conductive fine particles into a smooth shape with sharp corners, the region where the tunnel current flows on the surface of the conductive fine particles can be kept constant for a long period of time, and there is no initial fluctuation or drift of the resistance value. A highly stable strain resistance element can be realized.

Aluminum (Al), chromium (Cr),
Manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), palladium (Pd), silver (Ag), indium (In), Tin (Sn), platinum (Pt), gold (Au),
By using at least one metal selected from the group consisting of lead (Pb), conductive fine particles having a diameter of 1 to 50 nm could be produced with good reproducibility. In particular, when the electrically insulating material is composed of an oxide, the fine particles are composed of at least one metal selected from the group consisting of noble metals such as gold, silver, copper, platinum, and palladium. And the electrical characteristics can be prevented from changing over time.

By alternately or simultaneously depositing an electrically insulating substance and conductive fine particles on a substrate, a composite material in which conductive fine particles are dispersed at a desired density can be easily formed with good reproducibility. Was. The conductive fine particles formed by sputtering a metal material have relatively uniform particle diameters, so that the electrical characteristics of the element can be controlled with good reproducibility. In addition, an electrically insulating thin film formed by sputtering has dense and excellent insulating properties, so that an element with high stability and reliability can be realized.

The heat treatment of the composite material in which the conductive fine particles are dispersed changes the size and shape of the conductive fine particles and improves the crystallinity, so that the distance between the fine particles and the fine particle density can be controlled and the desired value can be obtained. An element having excellent characteristics can be realized.

(Embodiment 1) Hereinafter, an embodiment of a strain resistance element according to the present invention will be described in detail with reference to FIGS.

As shown in FIG. 3, the strain resistance element of the present embodiment has a quartz glass substrate 1 and an electrically insulating material layer (thickness: 0.04 to 2.0 μm) 3 supported on the substrate 1. And a pair of electrodes (thickness: 0.1 μm) in contact with the electrically insulating material layer 3.
m) 4 and 5. The size of the quartz glass substrate 1 is 3 mm in length, 5 mm in width, and 0.2 mm in thickness.
Was used. A plurality of conductive fine particles 2 are dispersed in the electrically insulating substance 3 so that a tunnel current flows when a voltage is applied between the pair of electrodes 4 and 5. As a result, the electrically insulating material layer 3 in which the conductive fine particles 2 are dispersed functions as a “strain resistor” or a “strain resistor layer”. The material of the electrically insulating material layer 3 of this embodiment is SiO ₂ , and the material of the conductive fine particles is gold (Au).
It is.

In this example, the above-described strain resistor layer was manufactured using the sputtering apparatus shown in FIG. As a sputtering target, a quartz (SiO ₂ ) glass target 6
And a gold (Au) target 7 were used. The substrate 8 (the substrate 1 in FIG. 3) is fixed to a substrate holder 10 provided with a heater 9, and is rotated by a rotation shaft directly connected to the substrate holder 10 so that the substrate 8 is over the target of either the SiO ₂ target 6 or the Au target 7. You can bring it. The position of the substrate 8 and the stay time above each target are controlled by a computer. In order to prevent contamination during sputtering, a shield plate 11 is provided so as to cover the periphery of each target and the extension thereof. Substrate 8
A mirror-polished quartz glass having a thickness of 0.2 mm was used. As a sputtering gas, argon or argon containing oxygen is used. The gas is introduced from a gas inlet 12 and a gas outlet 13 is connected to a vacuum exhaust system.
a, the substrate temperature was 200 ° C., the applied power to the SiO ₂ target 6 was 250 W, and the applied power to the gold target 7 was 10
W.

First, the substrate 8 is placed on the Au target 7 for 2 seconds.
Au microparticles were deposited in argon gas for a period of 00 seconds. Next, the substrate 8 is rotated and allowed to stay on the SiO ₂ target 6 for 5 minutes to deposit an SiO ₂ film having a thickness of 0.1 μm in an argon gas containing 10% oxygen. A layer (the electrically insulating material layer 3 in which the conductive fine particles 2 were dispersed) was formed. The temperature of the substrate holder 10 was maintained at room temperature to about 200 ° C. Observation of the cross section of the obtained SiO ₂ film in which the Au fine particles were dispersed by a transmission electron microscope revealed that the average particle size of Au was 5 nm. As the time for holding the substrate 8 on the Au target 7 is further increased, the particle size of the Au fine particles increases. If this time is set to a value exceeding, for example, about 600 seconds, each Au fine particle is connected to an adjacent Au fine particle and grows into a porous Au film. To form the strain resistor layer used in the present invention, Au
It is preferable to adjust the sputtering conditions so that the size of the fine particles does not become larger than 50 nm.

Next, a pair of electrodes 4 and 5 are formed on the surface of the strain resistor layer thus manufactured by a vacuum evaporation method. Thus, the strain resistance element shown in FIG. 3 was completed. Before the electrodes 4 and 5 are deposited, a portion of the Si where an electrode is to be formed is formed.
The O ₂ film was etched away using hydrofluoric acid to a thickness of about 0.1 μm. The electrodes 4 and 5 are made of 50n of chromium (Cr).
After depositing m, Au was deposited by depositing 0.1 μm. The electrode width was 3 mm and the electrode interval was 0.5 mm.

A method for forming another electrode will be described with reference to FIGS. 5 (a) to 5 (c). First, as shown in FIG. 5A, a strain resistor layer is formed on the substrate 1 by the above-described method. Next, as shown in FIG.
A pair of V-shaped grooves with respect to the surface of the substrate 1 are formed in the strain resistor layer. Finally, as shown in FIG. 5C, the electrodes 4 and 5 are formed in the V-shaped groove. By forming such a V-shaped groove, the area of electrical contact between the electrodes 4 and 5 and the conductive fine particles is effectively increased. Therefore, a reliable and stable contact is formed. The formation of such a V-shaped electrode has a particularly advantageous effect when the conductive fine particles are dispersed in a multilayer shape.

FIG. 6 shows the relationship between the strain measured by the strain resistance element shown in FIG. 3 and the resistance value. FIG. 6 shows that the resistance change rate (gauge factor) per unit strain is 15, which is nearly 10 times higher than the strain resistance element using the metal thin film. According to the strain resistance element of the present invention, a gauge factor of 5 to 80 can be obtained. Also, it was found that the resistance temperature characteristics in the temperature range from -40 ° C to 200 ° C were excellent at 10 ppm / ° C. FIG. 6 shows the change in the electric resistance between the electrodes due to the strain. However, it has been found that the magnitude of the strain can be detected with high accuracy by detecting the change in the capacitance due to the strain.

In the above example, the strain resistor layer was manufactured by sputtering the metal target and the insulator target once each, but, for example, the substrate 8 was placed on the metal target for 5 seconds and then on the insulator target. By repeating the operation of staying for 10 seconds about 300 times, a strain resistor layer containing conductive fine particles having a uniform particle size in a layer is formed, and a strain resistor layer having excellent resistance value can be manufactured. Was.

Also, the strain resistor layer could be manufactured by setting the substrate 8 above the space between the two targets 6 and 7 and simultaneously sputtering metal and an insulator.

The Au targets were aluminum (Al), chromium (Cr), manganese (Mn), iron (F
e), cobalt (Co), nickel (Ni), copper (C
u), zinc (Zn), gallium (Ga), palladium (Pd), silver (Ag), indium (In), tin (S
Even if the target is made of n), platinum (Pt) or lead (Pb), a strain-resistant material in which conductive fine particles having a particle size of 1 to 50 nm are dispersed can be obtained.

An insulator layer having a thin surface (having a thickness of 5 nm)
The conductive fine particles covered by the following method may be used. For example, a strain resistor layer through which a tunnel current flows can be obtained using Al fine particles whose surface is covered with an Al _x O _y layer having a thickness of about 1 nm. In this case, the fine particles may be in contact with each other via a thin Al _x O _y layer. This is because the tunnel current flows through the thin Al _x O _y layer. The thin insulating layer covering the surface of the conductive fine particles, for example, the Al _x O _y layer, may be formed by heat treatment after the conductive fine particles are dispersed in the electrically insulating material layer. The heat treatment causes the conductive fine particles to react with the electrically insulating material layer to form a thin insulating layer covering the surface of the conductive fine particles. Thereafter, the reaction between the conductive fine particles and the electrically insulating material layer proceeds. Without this, stable characteristics with little change over time can be exhibited.

In the above embodiment, the case where SiO ₂ was used as the electrically insulating material was described, but silicon nitride (Si ₃
Even if N ₄ ), aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), titanium oxide (TiO ₂ ), or hafnium oxide (HfO ₂ ) are used, a strain resistor layer excellent in corrosion resistance can be manufactured. These electrically insulating substances can be formed by sputtering an oxide or a nitride, but can also be formed by sputtering a semiconductor material such as silicon or aluminum or a metal material in an atmosphere containing oxygen or nitrogen. .

When an oxide is used as the electrically insulating substance, gold (Au), silver (Ag), copper (Cu), platinum (Pt), or palladium (Pd) is used as the conductive fine particles.
By using at least one metal selected from the above, an element having extremely excellent stability can be manufactured. It is considered that this is because the interface between the metal and the oxide is steep and stable.

As the structure of the strain resistance element, the above-described strain resistor layer may be formed after forming at least one pair of electrodes on the electrically insulating substrate. By doing so, the electrical connection between the electrode and the conductive fine particles can be made stable and reliable, and an element having excellent characteristics and quality can be manufactured over a long period of time. By further covering the strain resistor layer with another electrically insulating material layer, the stability is further increased and the quality is not deteriorated even in a corrosive atmosphere.

Although quartz glass was used as the substrate material, it could be used irrespective of the presence or absence of conductivity, such as a surface-polished stainless steel plate, a glass-coated iron plate, or a ceramic plate. When a material having a large coefficient of thermal expansion such as a metal is used as the substrate, a change in resistance value with temperature increases. This is because the distance between the conductive fine particles increases due to the thermal expansion of the substrate, and the resistance value increases. By utilizing this effect, a highly sensitive temperature sensor can be manufactured.

These strain resistive layers were able to reduce the hysteresis and the change with time of the strain-resistance value characteristics by performing the heat treatment. This heat treatment was suitably performed at a temperature between one fifth and three fifths of the melting point of the metal material used. It is considered that the characteristics are improved because the heat treatment increases the particle size and uniforms the particle size, and removes strains and defects in the conductive fine particle crystal. When a nitride material was used as the electrically insulating material, the particle size was slightly increased by the heat treatment, but the characteristics could be stabilized. In this case, the particle size could be controlled by the substrate temperature during sputtering.

By raising the substrate temperature during the sputtering or by performing heat treatment, the corners of the fine particles were rounded and smooth, but the smooth fine particles had better initial characteristics than the square fine particles. It is considered that this is because the tunnel current is easily affected by the state of the surface of the fine particles, and the fine particles having a smooth surface have a more stable surface, and a stable tunnel current flows.

Incidentally, instead of the above sputtering method,
An electrically insulating material layer in which conductive fine particles are dispersed may be formed by using a sol-gel method. In this case, for example, hydrochloric acid is added to a mixture of a silicon alkoxide solution and an aqueous solution of chloroauric acid, and the mixture is hydrolyzed.
dry. Thereafter, by firing at 700 to 800 ° C., a silica glass layer in which fine gold particles are dispersed is obtained.

Various mechanical quantity sensors can be formed using the above-described strain resistance element. If a beam is used as the base, it is possible to easily detect distortion due to deformation of the beam. FIG. 7 shows, for example, a sensor using a doubly supported beam as a base. The sensor shown in FIG. 7 includes a beam, members supporting both ends of the beam, a strain resistor layer formed on the beam, and a pair of electrodes provided on the strain resistor layer. When the beam is deformed by some external force (for example, pressure or acceleration), the deformation causes strain in the strain resistor layer. The strain changes the gap between the conductive fine particles, so that the magnitude of the tunnel current changes according to the change in the gap. The magnitude of the strain can be measured by comparing the magnitude of the tunnel current with the magnitude of the tunnel current flowing through the reference strain resistor layer (not shown).

It should be noted that a cantilever may be used as a substrate for supporting the strain resistor layer instead of the double-supported beam shown in FIG.

(Embodiment 2) In recent years, an atomic force microscope has been developed as a device capable of observing a solid surface in an atomic order. In an atomic force microscope, a probe having a length of 100 μm to 2 μm to detect a minute force is used.
A cantilever of about 00 μm is required. The force received when the tip of the probe approaches the atoms or molecules on the sample surface is detected by measuring the deflection of the cantilever. The deflection measurement method includes an optical lever method and an optical interference method. Normally, in atomic force microscopes, the smaller the device, the higher the resolution. However, a detection mechanism such as an optical lever for detecting the deflection of the cantilever is required, so there is a limit to miniaturization. . Furthermore, when an atomic force microscope is used in a vacuum, in a high-temperature environment, elements such as a laser light source and a photodiode used for optical leverage and optical interference are destroyed, so that the baking temperature of the chamber can be increased. However, there is a problem that it takes a long time to achieve an ultra-high vacuum.

Therefore, a silicon thin film whose resistance is reduced by doping is formed on the surface of the cantilever without providing an external deflection measuring section as described above, and the resistance change due to the deflection is measured using the piezoresistance effect. One that detects cantilever deflection has been developed.

Further, the cantilever is applied to an acceleration sensor or an ultrasonic sensor used in an automobile or the like. In these, too, the deflection of the cantilever using a doped silicon thin film or a piezoelectric thin film is used. Detected (Japanese Patent Laid-Open No. 4-164373, Japanese Patent Laid-Open No. 59-57
595).

However, the deflection detection method using the piezoresistance effect of a semiconductor thin film such as silicon has a problem that the resistance value is largely dependent on temperature and cannot be used in an environment where the temperature changes greatly. . In the deflection detection method using a piezoelectric thin film, dynamic (AC) deflection such as ultrasonic vibration can be detected with high sensitivity, but static (DC) deflection can be detected. There was a problem that it could not be done.

According to the present invention, by using the above-mentioned "strain resistor layer", a cantilever beam excellent in characteristics used for an atomic force microscope, an acceleration sensor, an ultrasonic sensor, and the like, and a method of manufacturing the same are provided. Can be provided.

Hereinafter, an embodiment of the cantilever according to the present invention will be described.

FIG. 8 is a schematic perspective view showing an embodiment of a cantilever according to the present invention. The thin film cantilever 23 of FIG.
One end is fixed to the glass substrate 24. Also,
A pair of electrodes 25, 2
5 are provided. Here, the thin film cantilever 23 is
It has a laminated structure including a 0.8 μm thick Si ₃ N ₄ thin film 21 and a strain resistor layer 22 made of a 0.1 μm thick SiO ₂ thin film in which Au fine particles are dispersed. The length of the thin-film cantilever 23 is 100 μm. A probe 26 made of the same material as the material of the thin-film cantilever 23 is provided at the tip of the thin-film cantilever 23.

The bending of the thin film cantilever 23 is caused by the electrode 2
It is detected by measuring the change in resistance between 5, 25. This resistance value changes due to strain inside the resistor layer 22 caused by the deflection of the thin-film cantilever 23. The relationship between the strain and the resistance value is substantially the same as that shown in FIG. As is clear from FIG. 6, the rate of change of the resistance value (gauge rate) with respect to the unit strain amount is 15, which indicates that highly sensitive deflection measurement is possible. Also, -40
The resistance temperature characteristic in the temperature range of
pm / ° C. The magnitude of the deflection could be detected with high accuracy by detecting the change in the capacitance due to the strain.

The thin-film cantilever 23 is attached to an atomic force microscope, and the deflection of the thin-film cantilever 23 generated when the probe 26 comes into contact with the sample surface is detected by measuring a resistance value. Scanning was performed while controlling the position of the sample so that the resistance value was constant. Thereby, an uneven image of the sample surface could be observed. If deflection is detected by this method, elements such as a laser light source and a photodiode become unnecessary. Then, even when performing an atomic force microscope measurement in an ultra-high vacuum, the baking of the chamber is easy, so that an ultra-high vacuum can be achieved in a relatively short time. Furthermore, because the temperature characteristics are excellent,
Atomic force microscopy at low or high temperatures could be performed relatively easily.

Next, a method for manufacturing the cantilever 23 will be described with reference to FIGS. 9 (a) to 9 (e).

First, as shown in FIG. 9A, an etch pit 27 is formed on the surface of a single crystal Si substrate 28 by anisotropic etching. The size of the etch pit 27
For example, it is about 5 μm × 5 μm, and the depth is about 3 μm. On the substrate 28 so as to cover the etch pit 27,
After depositing Cr (thickness: 50 nm) and Au (thickness: 500 nm) in this order, a pair of electrodes 25 was formed by photolithography. Electrodes 25, 25
Corresponds to the electrodes 25, 25 in FIG. The width of each electrode 25 was 3 mm, and the interval between the electrodes 25 was 20 μm.

Next, by the alternate sputtering method,
After depositing Au fine particles having an average particle size of 5 nm, a strain resistor layer 22 was formed by depositing a 0.1 μm thick SiO ₂ film using the same sputtering apparatus. Then, as shown in FIG. 9B, the surface of the strain resistor layer 22 formed as described above is formed by a CVD method.
An Si ₃ N ₄ film (0.8 μm thickness) 21 was deposited.

Next, as shown in FIG. 9C, these thin films 21 and 22 were processed into a cantilever shape by photolithography. Then, FIG.
As shown in (d), a part of the glass substrate 24 was anodically bonded onto the fixed portion of the cantilever 23. Then, FIG.
As shown in (e), the thin film cantilever 23 was formed by removing the Si substrate 28 by etching. In this case, by forming the etch pits 27 on the surface of the Si substrate 28 as described above, the thin-film cantilever 23 with the integrated probe 26 is obtained.

In the above embodiment, a cantilever for an atomic force microscope has been described as an example, but acceleration and ultrasonic waves can be detected with high sensitivity by a cantilever having substantially the same configuration. can do. Of course, the probe is not necessary for detecting acceleration or ultrasonic waves, but the weight is added to the cantilever using the manufacturing method for attaching the probe (that is, by forming a concave portion on the surface of the substrate). It can be formed and used to adjust the resonance frequency of a cantilever, which is particularly important as an ultrasonic sensor.

In the above embodiment, Au fine particles are used as the conductive fine particles, but the present invention is not limited to this. As the conductive fine particles, any material having conductivity may be used. In particular, a thermally and chemically stable material such as a noble metal is preferably used. For example, aluminum (Al), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (G
a), at least one metal selected from palladium (Pd), silver (Ag), indium (In), tin (Sn), platinum (Pt), gold (Au) and lead (Pb) can be used. . If the distance between the conductive fine particles is 5 nm or less, the rate of change of the resistance value with respect to the bending increases, and the accuracy of detecting the bending is improved. The size of the conductive fine particles is desirably 1 nm to 50 nm for manufacturing and for making the distance between the fine particles relatively uniform at the level of nm. It is important that the distance be large enough for the tunnel current to flow. Of course, it is not necessary to make the distance between all the particles existing between the electrodes large enough for the tunnel current to flow, and there is no problem even if there is an electrically short-circuited particle. That is, it is sufficient that there is a portion between the electrodes where no current flows unless a tunnel current is applied. The ratio of the conductive fine particles to the electrically insulating material in the portion where the current actually flows is preferably in the range of 15% to 70% in terms of volume ratio, since particularly excellent sensitivity can be obtained.

[0086] The Au fine particles were made of Al, Cr, Mn, Fe,
Co, Ni, Cu, Zn, Ga, Pd, Ag, In, S
Even if produced in place of n, Pt or Pb, the particle size is 1 nm to 5 nm.
A dispersion of 0 nm conductive fine particles was obtained.

The electrically insulating material may be any material such as an oxide, a nitride, and an organic material having low conductivity enough to detect a change in tunnel current.

The electrodes are formed after removing the electrically insulating material on the surface, for example, when the electrically conductive fine particles are covered with an electrically insulating material, so as to be surely electrically connected to the electrically conductive fine particles. There is a need.

[0089] Further, in the above embodiment, to form a resistance layer 22 by one by sputter once Au particles and the SiO ₂ film, respectively, for example, SiO ₂
By thinning the film and sputtering the Au fine particles and the SiO ₂ film several times, a resistive thin film containing conductive fine particles of uniform particle size in an electrically insulating material is formed, and the resistance value accuracy is excellent. A cantilever beam can be manufactured. Further, the resistor layer can be formed by simultaneously sputtering metal and an insulator.

Further, in the above embodiment, the case where SiO ₂ is used as the electrically insulating substance is described as an example, but the present invention is not necessarily limited to this. For example, silicon (Si), aluminum (Al), titanium (T
i), an oxide containing at least one selected from oxides of hafnium (Hf), nitrides of silicon (Si) and aluminum (Al) can be used. Si ₃ N ₄ , Al ₂ O ₃ , AlN, Ti
When O ₂ or HfO ₂ is used, a material excellent in corrosion resistance can be formed. These electrically insulating substances can be formed by sputtering an oxide or a nitride, but can also be formed by sputtering a semiconductor material such as Si or Al or a metal material in an atmosphere containing oxygen or nitrogen. be able to.

When oxide or nitride is used as the electrically insulating substance, Au, Ag, Cu,
By using at least one metal selected from Pt and Pd, it is possible to form the resistor layer 22 having extremely excellent stability. It is considered that this is because the interface between these metals and oxides or nitrides is steep and stable.

The pair of electrodes may have a configuration in which a resistor layer is sandwiched between metal thin films. According to this configuration, the electrical connection between the electrode and the conductive fine particles is stable and reliable.

In the above embodiment, the electrically insulating material is formed over the entire surface of the cantilever. However, it may be formed only on a portion of the cantilever where deflection occurs. In this case, if an electrically insulating substance is formed in the vicinity of the fixed portion of the cantilever where the amount of deflection becomes maximum, the sensitivity is increased.

By subjecting these resistor layers to heat treatment, the hysteresis and the change with time of the strain-resistance value characteristics are further reduced. This heat treatment was suitably performed at a temperature between one fifth and three fifths of the melting point of the metal material used. It is considered that the characteristics were improved because the heat treatment increased the particle size and uniformed the particle size, and removed strains and defects in the crystals of the conductive fine particles. When a nitride material is used as the electrically insulating substance, the increase in the particle size due to the heat treatment is slight, but the characteristics can be stabilized. In this case, the particle size can be controlled by the substrate temperature during sputtering.

In the above-described embodiment, the cantilever is formed after forming the resistor layer in which the conductive fine particles are dispersed in the electrically insulating substance. It is also possible to form a resistor layer using a sputtering method or the like.

(Embodiment 3) Conventionally, a mechanical rotary-top gyro has been used as an inertial navigation device for an airplane, a ship or the like. Since this gyro is high-precision, but large and expensive, tuning-fork and triangular prismatic vibration-type angular velocity sensors have been developed for home appliances and automobiles. A conventional vibration type angular velocity sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-264282.
The angular velocity sensor has a tuning fork type structure, and a vibration unit in which a drive element and a detection element are orthogonally joined is connected by a connection block.

When a voltage is applied to the drive element to cause it to vibrate, the monitor element vibrates via the connection block, and the entire tuning fork structure resonates. The drive voltage is controlled by monitoring the vibration amplitude and phase of the monitor element, and the drive vibration is stabilized. When an angular velocity ω occurs in the sensor axis direction, a Coriolis force Fc is generated in a direction perpendicular to the vibration direction of the sensing element. Since the pair of sensing elements are oscillating in opposite directions, each of the sensing elements is deformed in the opposite direction by the Coriolis force, and a charge is generated on the surface by a piezoelectric effect. Angular velocity can be detected.

However, in the conventional sensor, the piezoelectric element for driving, monitoring, or detecting element is processed with high precision, and if they are not assembled with high precision, the resonance frequency shifts or the attenuation characteristic varies. Angular velocity cannot be detected with high sensitivity. Further, since a sensor is formed by assembling some components, there is a problem in miniaturization and cost reduction.

FIG. 10 is a perspective view showing an embodiment of the angular velocity sensor according to the present invention. Hereinafter, the configuration will be described with reference to FIG.

This angular velocity sensor includes a cantilever 34 extending from a fixed portion 33 in a direction 39, a fixed portion 33, a piezoelectric driving element 32 for vibrating the cantilever 34, and a substrate 31 for supporting these. ing. The cantilever 34 is made of silicon oxide having a thickness of 5 μm, has a length of 250 μm, and a width of 25 μm.
μm. The resonance frequency of the cantilever 34 is 60 kHz.
z. The cantilever 34 and its fixing part 33 can be easily manufactured from a silicon wafer having an oxide film formed on the surface thereof by using a semiconductor process technique. The fixing part 33 is fixed to the electrode 37 of the piezoelectric driving element 32 by an adhesive. Have been.

The substrate 31 may be made of various materials such as glass, metal, and resin according to the intended use. By using a conductive material such as a metal as the material of the substrate 31, the substrate 31 can function as the other electrode of the piezoelectric driving element 32.

On the cantilever 34, a strain resistance element 35 is provided.
a and 35b are provided. This strain resistance element 35a,
As 35b, the above-described strain resistance element according to the present invention is used. The strain resistance elements 35a and 35b are formed by alternately sputtering gold and silicon oxide to form a 1 μm thick strain resistance layer made of silicon oxide in which fine gold particles are dispersed, Is processed to have a pattern shown by etching. These steps can be performed before the fabrication of the cantilever 34 is completed. Specifically, after forming a silicon oxide film on the surface of a silicon wafer, a strain resistor layer is formed on the silicon oxide film. Thereafter, the strain resistive element layer is processed, and a strain resistive element having the illustrated pattern is formed on a region of the silicon oxide film to be processed into the cantilever 34. In this embodiment, the strain resistance elements are arranged so as to extend in a direction making an angle of about 30 degrees with a direction (length direction) 39 in which the cantilever 34 extends. This angle is not limited to about 30 degrees, and it is sufficient that the strain resistance elements 35a and 35b extend in a direction that is not parallel to the direction 39. The sizes of the strain resistance elements 35a and 35b of this embodiment are respectively
Length: 10 to 100 μm, width: 3 to 10 μm.

According to the angular velocity sensor shown in FIG.
When a torsional stress occurs around 9, one of the two strain resistance elements 35a and 35b expands and the other contracts. The two strain resistance elements 35a and 35b are electrically connected on the free end side of the cantilever 34, and are connected to an extraction electrode 36c made of a metal thin film. The fixed ends of the strain resistance elements 35a and 35b are connected to extraction electrodes 36a and 36b made of a metal thin film, respectively. These extraction electrodes 36a, 36b, and 36c are formed before or after manufacturing the strain resistance elements 35a and 35b.
It can be formed of a metal thin film such as gold. As the strain resistance elements 35a and 35b, it is particularly preferable to use the strain resistance element of Example 1, that is, an electrically insulating material layer in which a plurality of conductive fine particles are dispersed, from the viewpoint of sensitivity and the like.

FIG. 11 is a circuit diagram showing the connection between the lead electrodes 36a, 36b and 36c of the strain resistance elements 35a and 35b and the detection circuit.

Reference numerals 40a and 40b denote strain resistance elements 3 respectively.
5a and 35b are resistance elements having substantially the same resistance values. These strain resistance elements 35a and 35b and the resistance element 4
Oa and 40b form a Wheatstone bridge. The resistance elements 40 a and 40 b can be formed using a strain resistance element, and can be simultaneously formed on the surface oxide film of the cantilever fixing portion 33 when the strain resistance element 35 is manufactured. Since no bending stress is applied to the fixing portion 33, the resistance value does not change even when the cantilever is driven to vibrate. Furthermore, since the resistance element 40 is made of the same material as the strain resistance element 35, the temperature changes in the resistance value cancel each other out, so that an angular velocity sensor with excellent temperature characteristics can be manufactured. The power supply circuit 42 includes the electrode 36c and the electrode 41.
The detection circuit 43 is for amplifying and detecting the voltage between the electrodes 36a and 36b.

In the angular velocity sensor configured as described above, an AC voltage is applied to the piezoelectric driving element 32 to vibrate the cantilever 34 in a direction 38 perpendicular to the main surface thereof. Due to this vibration, the resistance values of the strain resistance elements 35a and 35b repeatedly increase and decrease, but since there is no difference between the respective resistance values, almost no voltage is generated between the electrodes 36a and 36b.
However, when a rotational force about the direction 39 is applied, the direction of the angular velocity vector is directed to the length direction 39 of the cantilever 34, and is therefore perpendicular to the rotation axis (direction 39) and the vibration direction (direction 38). A Coriolis force is generated in the direction, and the vibration direction of the cantilever 34 shifts. Therefore, a torsional stress is generated in the cantilever 34, and a tensile stress is applied to one of the strain resistance elements 35a and 35b, and a compressive stress is applied to the other. Voltage is generated. The magnitude of the angular velocity can be measured by amplifying and detecting this voltage by the detection circuit 43. In addition, since the polarity of this voltage is inverted depending on the rotation direction, the rotation direction can be detected.

The magnitude of the amplitude of the cantilever in the 38 direction can be detected by monitoring the magnitude of the change in the resistance value of one of the strain resistance elements. Specifically, for example, the electrode 3
The amplitude is detected by monitoring the voltage between 6a and the node 41 by the detection circuit 43, and the magnitude of the amplitude can be kept constant by feedback-controlling the piezoelectric driving element 32 with this signal. As such a strain resistance element for monitoring, a third strain resistance element dedicated to detecting the amplitude of the cantilever can be provided in the length direction of the cantilever.

Circuit for piezoelectric drive element 32, electrode 36a
A circuit that amplifies and detects the voltage generated between the circuit and 36b, a circuit that monitors the magnitude of the amplitude of the cantilever, a circuit that performs feedback control of the piezoelectric driving element 32, and a resistance value for the bridge circuit is a cantilever. It is also possible to make them in advance in the silicon substrate of the beam fixing part.
Therefore, there is no need to manufacture a circuit unit separately from the sensor unit, connect them, and connect them by wiring, so that the sensor can be manufactured extremely small.

In this embodiment, a rectangular cantilever as shown in FIG. 10 is used as the cantilever. However, as shown in FIG. 12, the width of the cantilever where the strain resistance element is provided is reduced. By reducing the width, the sensitivity can be increased although the response speed is reduced. This is because the torsional stress acting in the direction 39 can be concentrated on the narrow portion.
The same effect can be obtained by reducing the thickness of the cantilever where the strain resistance element is provided.

As the strain resistance element, a thin film resistance in which conductive fine particles are dispersed in an insulator is used. However, a semiconductor diffusion resistance in which a semiconductor such as silicon is doped with impurities, a thin film metal resistance, or a thin film resistance such as germanium or amorphous silicon is used. Thin film semiconductor resistors can also be used. When using a semiconductor diffusion resistor, the cantilever is made of the same semiconductor and the surface is doped with impurities, so that the strain resistance element can be easily formed on the surface of the cantilever, and the advantage that the sensitivity is large. However, there is a disadvantage that the temperature characteristics are poor. Thin-film metal resistors have excellent temperature characteristics but low sensitivity, and semiconductor thin-film resistors exhibit intermediate characteristics between semiconductor diffusion resistance and thin-film metal resistance. However, overall, thin-film resistors with conductive fine particles dispersed in an insulator have excellent temperature characteristics and sensitivity,
The manufacturing method is also easy, and a sensor having excellent stability can be manufactured with good reproducibility. As conductive fine particles, gold, platinum,
Noble metals such as silver and copper exhibit particularly excellent properties.

Although the case where a silicon oxide thin film is used as the cantilever has been described, a silicon cantilever manufactured from a silicon wafer by a micromachining technique or a silicon nitride thin film cantilever may also be used. it can.
The silicon cantilever has an advantage that a strain resistance element can be integrally formed by ion-implanting boron or the like into the surface.

The cantilever made of silicon nitride has high breaking strength.
A sensor excellent in impact resistance can be manufactured, and the silicon oxide cantilever shown in the embodiment can have a small coefficient of thermal expansion and excellent heat resistance and temperature characteristics. In particular, a sensor in which a strain resistance element in which conductive fine particles are dispersed in a silicon oxide thin film is disposed on the surface of a silicon oxide cantilever has excellent heat resistance and temperature characteristics, and long-term reliability is required. It is most suitable as a vehicle angular velocity sensor.

[0113]

According to the physical quantity sensor element of the present invention,
Since a mechanical quantity such as strain is measured by a tunnel current flowing through a small gap between the conductive fine particles, excellent characteristics such as a high sensitivity to the mechanical quantity such as strain and a reduction in temperature change can be exhibited. Further, since a metal material or an electrical insulating material having excellent corrosion resistance can be used, a strain resistance element having excellent reliability and long-term stability can be provided. The strain resistance element can be used for an acceleration sensor, an impact sensor, a pressure sensor, or the like by processing it into a cantilever shape or by bonding it to a soft resin substrate or the like. Further, a substrate having a large thermal expansion coefficient can be used as a temperature sensor by installing it in a portion that is not subjected to distortion.

According to the method of manufacturing a dynamic quantity sensor of the present invention, a sensor having a strain-resistor layer having excellent characteristics in which the kind of metal, the size and density of conductive fine particles, the distance between fine particles, and the like can be easily controlled is provided. It can be manufactured with good reproducibility.

When a strain resistor layer of an electrically insulating material layer in which conductive fine particles are dispersed is provided on a beam-like substrate such as a cantilever, a tunnel current flowing through a slight gap between the conductive fine particles can be obtained. Accordingly, since the deflection can be measured, a cantilever having a deflection detection unit that has high sensitivity for detecting the deflection of the cantilever, has excellent temperature characteristics, and operates stably for a long period of time is realized.

Further, according to the angular velocity sensor of the present invention,
Since a semiconductor process technology capable of high-precision processing can be used, a highly sensitive and small angular velocity sensor can be manufactured at a low price. In addition, since the cantilever can be manufactured using a semiconductor substrate such as silicon, a circuit for amplifying and detecting a small change in the resistance value of the strain resistance element and a circuit for monitoring the amplitude of the cantilever are fixed to the cantilever. It is possible to make it into a part, and it is possible to further reduce the size and weight.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view schematically illustrating a strain resistance element according to the present invention, and FIG. 1B is a cross-sectional view schematically illustrating another strain resistance element according to the present invention.

FIGS. 2A to 2C are plan views showing a dispersion state of conductive fine particles in an electrically insulating material layer.

FIG. 3 is a sectional view of an embodiment of a strain resistance element according to the present invention.

FIG. 4 is a schematic view of a sputtering apparatus used when manufacturing the embodiment of FIG.

FIGS. 5A to 5C are process plan views illustrating an example of a method of forming an electrode.

FIG. 6 is a graph showing a change in strain-resistance value measured for the strain resistance element of the present invention.

FIG. 7 is a perspective view showing a structure in which a strain resistor layer is provided on a beam-shaped base.

FIG. 8 is a schematic perspective view showing a cantilever embodiment according to the present invention.

FIGS. 9A to 9E are process cross-sectional views illustrating a method for manufacturing the cantilever of FIG. 8;

FIG. 10 is a perspective view of a detection unit of the angular velocity sensor according to the present invention.

FIG. 11 is an equivalent circuit diagram of a connection between a detection unit and a detection circuit of the angular velocity sensor according to the present invention.

FIG. 12 is a perspective view of a detection unit of another angular velocity sensor according to the present invention.

[Explanation of symbols]

1 substrate 2 conductive particles 3 electrically insulating material 4 electrode 5 electrode 6 Target 7 Target 8 substrate 9 heater 10 substrate holder 11 shield plate 12 gas inlet 13 gas outlet 21 Si ₃ N ₄ film 22 resistor layer 23 thin film Cantilever 24 Glass substrate 25 Electrode 26 Probe 27 Etch pit 28 Si substrate 31 Substrate 32 Piezoelectric 33 Cantilever fixing part 34 Cantilever 35 a, 35 b Strain resistance element 36 a, 36 b, 36 c Lead-out electrode 37 Piezoelectric electrode 38 Vibration direction 39 Rotation direction 40a, 40b Resistor 41 Electrode 42 Power supply circuit 43 Detection circuit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI G01L 9/04 101 G01L 9/04 101 G01P 15/08 G01P 15/12 15/12 H01L 21/203 S H01L 21/203 29 / 84 A 29/84 21/316 Y // H01L 21/316 G01P 15/08 Z (72) Inventor Yoshio Manabe 1006 Ojidoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Masaru Yoshida Osaka 1006, Kadoma, Kamon, Fumonma-shi Matsushita Electric Industrial Co., Ltd. (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 49/00 H01L 41/08 G01C 17/00 G01L 1/00 G01L 7/00 G01D 5/00 B81B 3/00

Claims (24)

(57) [Claims] 1. A physical quantity sensor comprising: an electrically insulating material layer; and at least a pair of electrodes in contact with the electrically insulating material layer, wherein the at least one pair of electrodes is provided in the electrically insulating material layer. A dynamic quantity sensor in which a plurality of conductive fine particles are dispersed so that a tunnel current flows when a voltage is applied between the conductive fine particles, and a physical quantity related to an interval between the conductive fine particles is detected based on the tunnel current. 2. The physical quantity sensor according to claim 1, further comprising a substrate that supports the electrically insulating material layer. 3. The physical quantity sensor according to claim 2, wherein the base is a substrate on a flat plate. 4. The physical quantity sensor according to claim 2, wherein the base is a beam having both ends fixed. 5. The physical quantity sensor according to claim 2, wherein the base is a cantilever having one end fixed. 6. The conductive fine particles have a diameter of 1 nm to 5 nm.
The physical quantity sensor according to claim 1, which has a thickness of 0 nm. 7. The physical quantity sensor according to claim 1, wherein the conductive fine particles are dispersed in a layer form in the electrically insulating material layer. 8. The physical quantity sensor according to claim 1, wherein a distance between the conductive fine particles is 5 nm or less. 9. The method according to claim 1, wherein the conductive fine particles are made of aluminum (A).
l), chromium (Cr), manganese (Mn), iron (F
e), cobalt (Co), nickel (Ni), copper (C
u), zinc (Zn), gallium (Ga), palladium (Pd), silver (Ag), indium (In), tin (S
The physical quantity sensor according to claim 1, wherein the physical quantity sensor is formed of at least one metal selected from the group consisting of n), platinum (Pt), gold (Au), and lead (Pb). 10. The electrically insulating material layer is formed of an oxide, and the conductive fine particles are made of gold (Au), silver (Ag), copper (Cu), platinum (Pt), or palladium (Pd). 2. The physical quantity sensor according to claim 1, wherein the physical quantity sensor is formed from at least one metal selected from the group consisting of: 11. The electric insulating material layer is made of silicon (S
i), at least one selected from the group consisting of oxides of aluminum (Al), titanium (Ti), hafnium (Hf), silicon (Si), and nitrides of aluminum (Al). Item 2. The physical quantity sensor according to Item 1. 12. An electric insulating material layer, and at least a pair of electrodes in contact with the electric insulating material layer, wherein a strain generated in the electric insulating layer is detected based on a current flowing between the pair of electrodes. A plurality of conductive fine particles are dispersed in the electrically insulating material so that a tunnel current flows when a voltage is applied between the at least one pair of electrodes. element. 13. The conductive fine particles have a diameter of 1 nm to 1 nm.
The strain resistance element according to claim 12, which has a thickness of 50 nm. 14. The strain-resistant element according to claim 12, wherein the conductive fine particles are dispersed in a layer in the electrically insulating material layer. 15. The distance between the conductive fine particles is 5 nm.
The strain resistance element according to claim 12, wherein: 16. The conductive fine particles include aluminum (Al), chromium (Cr), manganese (Mn), and iron (F).
e), cobalt (Co), nickel (Ni), copper (C
u), zinc (Zn), gallium (Ga), palladium (Pd), silver (Ag), indium (In), tin (S
The strain resistance element according to claim 12, wherein the strain resistance element is formed of at least one metal selected from the group consisting of n), platinum (Pt), gold (Au), and lead (Pb). 17. The electric insulating material layer is formed of an oxide, and the conductive fine particles are made of gold (Au), silver (Ag), copper (C).
The strain resistance element according to claim 12, wherein the strain resistance element is formed of at least one metal selected from the group consisting of u), platinum (Pt), and palladium (Pd). 18. The method according to claim 18, wherein the electrically insulating material layer comprises silicon (S
i), at least one selected from the group consisting of oxides of aluminum (Al), titanium (Ti), hafnium (Hf), silicon (Si), and nitrides of aluminum (Al). Item 13. The strain resistance element according to Item 12. 19. The strain resistive element according to claim 12, wherein a plurality of the electrically insulating material layers and the electrodes are laminated. 20. A method for producing a strain-resistant element, comprising: a step of forming an electrically insulating material layer in which conductive fine particles are dispersed; and a step of providing at least a pair of electrodes on the electrically insulating material layer. Then, the step of forming the electrically insulating material layer includes a step of alternately depositing the electrically insulating material and the conductive fine particles. 21. A method for producing a strain-resistant element, comprising: a step of forming an electric insulating material layer in which conductive fine particles are dispersed; and a step of providing at least a pair of electrodes in the electric insulating material layer. And a step of heat-treating the electrically insulating material layer in which the conductive fine particles are dispersed, thereby controlling the size of the conductive fine particles. 22. A step of providing a pair of electrodes on a substrate ; a step of forming a resistor layer including an electrically insulating material layer in which conductive fine particles are dispersed on each electrode and on the substrate; Etching a part of the body layer to form a beam; and removing at least a portion of the substrate located under the beam-shaped resistor layer to form a beam. A method for manufacturing a physical quantity sensor, comprising: 23. The method according to claim 22, wherein the step of forming the resistor layer includes the step of alternately depositing the electrically insulating substance and the conductive fine particles. 24. The method of manufacturing a physical quantity sensor according to claim 22, further comprising a step of subjecting said resistor layer to a heat treatment.